We often hear that expression, "No Foot, No Horse". The same can be said for the horse's legs. The horse's leg is a very complex, intricate design of tendons and ligaments that act as connectors to the bones and hoof. The weaving in and out of all those structures creates a highly function tensile structure that is also very fragile.
It is important to understand the proper maintenance of the leg, from the shoulder down to the hoof. I learned years ago, while working at the race track, how the shoulder can affect the tendons. If the shoulder is tight, it will be pulling on the tendons and cause stress that can cause serious damage. It is not something that we think about, but shoulder tension can be a root cause for many a bowed tendon.
I would make it a part of your daily routine to check the limberness of the shoulder. Perhaps ask your massage therapist to report to you on the flexibility of the shoulder and set up an exercise routine that you can work with. You can help keep the shoulder limber with a good liniment and some magnet or laser therapy, as well.
The angles of the hoof can affect the tendons and ligaments as well. If the heel is not set at a proper angle you may be asking the tendon to be longer than is natural for that horse. I would consult with your farrier to make sure that your horse's feet are shod in such a way as to support the tendons and not stress them.
You can alleviate a lot of tendon and ligament injuries by knowing how to properly maintain the legs. Make sure the legs are properly bandaged to avoid any bandage bows. Think before turning your horse out or riding him in a muddy field. One slip in the mud could torque his tendon and do irreparable damage. Look into the best way to support the leg with exercise boots.(See our video)
The next time you are able to watch some horses moving -- whether being ridden by someone or running freely in the field -- stop and watch them. Take a close look at the leg and the dynamics of its movement. You can get an idea by looking at some of the veterinary, anatomy or kinesiology books out on the market. This will give you a greater understanding of the biomechanics of the tendons and ligaments and how they work. By keeping all the functions in perspective you will know how to support the health of the legs and how to work with them should they get injured.